See an ENT. An Ear Nose and Throat specialist needs to take a look in that ear and determine exactly what is going on...it may not be a bacterial infection at all! Treatment will depend on what they find. Good luck!
Need ear drops. What you are describing sounds like an otitis externa (swimmer's ear). If this was an otitis media (ear infection) with a perforated ear drum it would likely be pus like fluid. If you have been swimming recently then swimmer's ear is more likely. Simmer's ear usually hurts more than otitis media. Antibiotic ear drops and abstaining from swimming for about a week is the treatment.
If given enough time. And no complications, but, is it an external or middle ear infection? Most middle ear infections are viral and don't need an antibiotic, but the complications / secondary bacterial infection may ensue and necessitate therapy. External ear infections are several, can be fungal / bacterial, and the ears and all the body usually clear and rid the infection, but time/other factors may not be in favor.
Many do...but... Most of these, including those caused by bacteria could self heal in a person with a normal immune system. It may take 3 months, but people had them long before we had antibiotics to treat them. However, there are also risks. A complication in that era that is still possible today includes progression to a dangerous infection of the mastoid air cells, behind the ears.